There is no one breeding Leafy's. Public Aquariums have been succsessful a handful of time breeding Weedy seadragon's but I really mean a handful of times.
There is a guy, David and his wife Tracy, in Australia that have some Leafy's, to my knowledge they have never been able to breed them. I think he would have mentioned it if they did.
There are som ehobbyist in Hong Kong who keep them, they have far less restrictions on imports there.
Leafy's are impracticle for the average hobbyist to keep because of the size tank they need and there cost. They are strictly protected in Australia, and I hope they stay that way.
There was a LFS here that was selling them about 6 years ago for only 1g. Kind of a bargin no? They have not had any for some time.